Plasma creation via nonaqueous optical breakdown of laser pulse energy for breakup of vascular calcium

ABSTRACT

A catheter system for treating a treatment site within or adjacent to a blood vessel includes a power source, a light guide and a plasma target. In various embodiments, the light guide receives power from the power source. The light guide has a distal tip, and the light guide emits light energy in a direction away from the distal tip. The plasma target is spaced apart from the distal tip of the light guide by a target gap distance. The plasma target is configured to receive light energy from the light guide so that a plasma bubble is generated at the plasma target. The power source can be a laser and the light guide can be an optical fiber. In certain embodiments, the catheter system can also an inflatable balloon that encircles the distal tip of the light guide. The plasma target can be positioned within the inflatable balloon. The target gap distance can be greater than 1 μm. The plasma target can have a target face that receives the light energy from the light guide. The target face can be angled relative to a direction the light energy is emitted to the plasma target. The plasma target can be formed from one or more of tungsten, tantalum, platinum, molybdenum, niobium, iridium, magnesium oxide, beryllium oxide, tungsten carbide, titanium nitride, titanium carbonitride and titanium carbide.

RELATED APPLICATIONS

This application claims priority on U.S. Provisional Application Ser.No. 62/863,506, filed on Jun. 19, 2019, and on U.S. ProvisionalApplication Ser. No. 62/965,069, filed on Jan. 23, 2020. To the extentpermitted, the contents of U.S. Provisional Application Ser. Nos.62/863,506 and 62/965,069 are incorporated in their entirety herein byreference.

BACKGROUND

Vascular lesions within and adjacent to vessels in the body can beassociated with an increased risk for major adverse events, such asmyocardial infarction, embolism, deep vein thrombosis, stroke, and thelike. Severe vascular lesions can be difficult to treat and achievepatency for a physician in a clinical setting.

Vascular lesions may be treated using interventions such as drugtherapy, balloon angioplasty, atherectomy, stent placement, vasculargraft bypass, to name a few. Such interventions may not always be idealor may require subsequent treatment to address the lesion.

Creation of a plasma via optical breakdown of an aqueous solutionrequires a significant amount of energy in a short amount of time uponwhich it is converted into a therapeutic bubble and/or a therapeuticpressure wave. With sufficiently high energy and short pulse durations,there is potential to damage a distal end of a light guide used todeliver light energy to generate the plasma. A means to enhance theconversion efficiency of the light energy to (plasma) pressure wave andbubble growth would reduce the required power handling requirements ofthe optical delivery system. Therefore, less input energy would berequired for an equivalent therapy while minimizing potential damage tothe light guide.

Creation of the plasma near the distal end of a small diameter lightguide as in the case of aqueous optical breakdown as one method for anintravascular lithotripsy catheter has the potential for self-damage dueto its proximity to the plasma creation and/or the pressure wave, highplasma temperatures, and waterjet from collapse of the bubble, asnon-exclusive examples.

SUMMARY

This summary is an overview of some of the teachings of the presentapplication and is not intended to be an exclusive or exhaustivetreatment of the present subject matter. Further details are found inthe detailed description and appended claims. Other aspects will beapparent to persons skilled in the art upon reading and understandingthe following detailed description and viewing the drawings that form apart thereof, each of which is not to be taken in a limiting sense. Thescope herein is defined by the appended claims and their legalequivalents.

The present invention is directed toward a catheter system for treatinga treatment site within or adjacent to a blood vessel. In certainembodiments, the catheter system includes a power source, a light guideand a plasma target. The light guide receives power from the powersource. The light guide has a distal tip, and the light guide emitslight energy in a direction away from the distal tip. The plasma targetis spaced apart from the distal tip of the light guide by a target gapdistance. The plasma target is configured to receive light energy fromthe light guide so that a plasma is generated at the plasma target uponreceiving the light energy from the light guide.

In some embodiments, the power source is a laser. In variousembodiments, the light guide is an optical fiber.

In certain embodiments, the catheter system can also include aninflatable balloon that encircles the distal tip of the light guide.

In various embodiments, the catheter system can also include aninflatable balloon. In some such embodiments, the plasma target can bepositioned within the inflatable balloon.

In some embodiments, the target gap distance is greater than 1 μm, 10μm, 100 μm, 1 mm, 2 mm, 3 mm, 5 mm and/or 1 cm.

In various embodiments, the plasma target can have a substantiallycircular cross-sectional configuration, a substantially squarecross-sectional configuration, a substantially rectangularcross-sectional configuration, a substantially oval cross-sectionalconfiguration, a substantially pentagonal cross-sectional configuration,a substantially hexagonal cross-sectional configuration, a substantiallyoctagonal cross-sectional configuration, a polygonal cross-sectionalconfiguration, a parallelogram cross-sectional configuration, atrapezoidal cross-sectional configuration or a substantiallydiamond-shaped cross-sectional configuration.

In certain embodiments, the catheter system can also include a guidewirelumen. In some such embodiments, the light guide can be coupled to theguidewire lumen.

In some embodiments, the plasma target has a target face that receivesthe light energy from the light guide. In various embodiments, thetarget face has an angle that is substantially orthogonal relative to adirection the light energy is emitted to the plasma target. In variousembodiments, the target face has an angle that is greater thanapproximately 45 degrees and less than approximately 135 degreesrelative to a direction the light energy is emitted to the plasmatarget. In certain embodiments, the target face can have an angle thatis greater than zero degrees and less than 180 degrees relative to adirection the light energy is emitted to the plasma target.

In various embodiments, the light guide includes a distal region havinga longitudinal axis. The direction the light energy is emitted can besubstantially along the longitudinal axis of the distal region.Alternatively, the direction the light energy is emitted can besubstantially perpendicular to the longitudinal axis of the distalregion. Still alternatively, the direction the light energy is emittedcan be angled relative to the longitudinal axis of the distal region.For example, in some embodiments, the direction the light energy isemitted has an angle relative to the longitudinal axis that is greaterthan zero degrees and less than 180 degrees. In various embodiments, thedirection the light energy is emitted can have an angle relative to thelongitudinal axis that is greater than 45 degrees and less than 135degrees.

In certain embodiments, the catheter system can include a plurality ofplasma targets that are spaced apart from the distal tip of the lightguide. In some such embodiments, at least one of the plurality of plasmatargets can be configured to receive light energy from the light guide.

In various embodiments, the plasma target can be at least partiallyformed from one of stainless steel and its variants, tungsten, tantalum,platinum, molybdenum, niobium, and iridium.

In some embodiments, the plasma target can be at least partially formedfrom one of magnesium oxide, beryllium oxide, tungsten carbide, titaniumnitride, titanium carbonitride and titanium carbide.

In certain embodiments, the plasma target can be at least partiallyformed from one of diamond CVD and diamond.

In various embodiments, the plasma target can be at least partiallyformed from a transition metal, a metal alloy and/or a ceramic material.

In some embodiments, the plasma target can be fixedly coupled to thelight guide. Alternatively, the plasma target can be movably coupled tothe light guide. Still alternatively, the plasma target can be uncoupledfrom the light guide.

In some applications, the catheter system can include a guidewire lumen.In some such embodiments, the plasma target can substantially encirclethe guidewire lumen.

In certain embodiments, the target face can include one or more surfacefeatures, which can include one or more of an indentation, a projectionand a beveled edge.

In some embodiments, the target face can have a conical configuration, apyramidal configuration, a dome-shaped configuration, a concaveconfiguration, a convex configuration, a multi-faceted configuration, acoiled configuration, a spring-like configuration and/or a somewhatspiral configuration.

In various embodiments, the plasma target can be movable relative to thelight guide. In some embodiments, the plasma target can bespring-loaded.

In certain embodiments, the catheter system can include a guidewirelumen, and the plasma target can be secured or otherwise coupled to theguidewire lumen.

In some embodiments, the catheter system can include a second lightguide that receives power from the power source. The second light guidecan have a second distal tip. The second light guide can emit lightenergy in a direction away from the second distal tip toward the plasmatarget. The plasma target can be spaced apart from the second distal tipof the second light guide. The plasma target can be configured toreceive light energy from the second light guide so that a second plasmais generated at the plasma target upon receiving the light energy fromthe second light guide.

In certain embodiments, the catheter system can include a second lightguide and a second plasma target. The second light guide can receivepower from the power source. The second light guide can have a seconddistal tip. The second light guide can emit light energy in a directionaway from the second distal tip toward the second plasma target. Thesecond plasma target can be spaced apart from the plasma target and thesecond distal tip of the second light guide. The second plasma targetcan be configured to receive light energy from the second light guide sothat a second plasma is generated at the second plasma target uponreceiving the light energy from the second light guide.

In various embodiments, present invention can also be directed toward amethod for creating plasma to optically break up vascular calcium in ablood vessel using laser pulse energy. In certain embodiments, themethod includes the step of providing any one of the catheter systemsshown and/or described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself,both as to its structure and its operation, will be best understood fromthe accompanying drawings, taken in conjunction with the accompanyingdescription, in which similar reference characters refer to similarparts, and in which:

FIG. 1 is a schematic cross-sectional view of a catheter system havingfeatures of the present invention in accordance with various embodimentsherein;

FIG. 2 is a simplified schematic side view of one embodiment of aportion of the catheter system, including one embodiment of a portion ofa catheter;

FIG. 3A is a simplified schematic side view of one embodiment of aportion of the catheter system, including another embodiment of aportion of the catheter, shown in an inflated state;

FIG. 3B is a simplified schematic side view of the portion of thecatheter illustrated in FIG. 3A, shown in a deflated state;

FIG. 4 is a simplified schematic side view of one embodiment of aportion of the catheter system, including another embodiment of aportion of the catheter;

FIG. 5 is a simplified schematic side view of one embodiment of aportion of the catheter system, including another embodiment of aportion of the catheter;

FIG. 6 is a simplified schematic side view of one embodiment of aportion of the catheter system, including another embodiment of aportion of the catheter;

FIG. 7A is a simplified schematic side view of one embodiment of aportion of the catheter system, including another embodiment of aportion of the catheter;

FIG. 7B is a simplified schematic side view of one embodiment of aportion of the catheter system, including another embodiment of aportion of the catheter;

FIG. 8 is a schematic cross-sectional view of the catheter system takenon line 8-8 in FIG. 1 ;

FIG. 9 is a schematic cross-sectional view of another embodiment of thecatheter system;

FIG. 10 is a schematic cross-sectional view of yet another embodiment ofthe catheter system;

FIG. 11 is a schematic cross-sectional view of still another embodimentof the catheter system;

FIG. 12 is a schematic cross-sectional view of a portion of the cathetersystem including one embodiment of a distal portion of a light guide;

FIG. 13 is a schematic cross-sectional view of a portion of the cathetersystem including an embodiment of the distal portion of the light guide;

FIG. 14 is a schematic cross-sectional view of a portion of the cathetersystem including another embodiment of the distal portion of the lightguide;

FIG. 15 is a schematic cross-sectional view of a portion of the cathetersystem including yet another embodiment of the distal portion of thelight guide;

FIG. 16 is a simplified schematic side view of a portion of oneembodiment of the catheter, including an embodiment of a portion of aplasma target;

FIGS. 16A-16J are cross-sectional views of various embodiments of theplasma target taken on line 16-16 in FIG. 16 ;

FIG. 17A-17H are perspective views of various embodiments of a portionof the plasma target having a target face;

FIG. 18 is a cross-sectional view of a portion of the catheter systemincluding one embodiment of a portion of the catheter;

FIG. 19 is a cross-sectional view of a portion of the catheter systemincluding another embodiment of a portion of the catheter;

FIG. 20 is a cross-sectional view of a portion of the catheter systemincluding another embodiment of a portion of the catheter; and

FIG. 21 is a cross-sectional view of a portion of the catheter systemincluding another embodiment of a portion of the catheter.

While embodiments are susceptible to various modifications andalternative forms, specifics thereof have been shown by way of exampleand drawings, and will be described in detail. It should be understood,however, that the scope herein is not limited to the particular aspectsdescribed. On the contrary, the intention is to cover modifications,equivalents, and alternatives falling within the spirit and scopeherein.

DESCRIPTION

Treatment of vascular lesions can reduce major adverse events or deathin affected subjects. A major adverse event is one that can occuranywhere within the body due to the presence of a vascular lesion. Majoradverse events can include, but are not limited to major adverse cardiacevents, major adverse events in the peripheral or central vasculature,major adverse events in the brain, major adverse events in themusculature, or major adverse events in any of the internal organs.

In various embodiments, the systems and methods disclosed hereindescribe the use of a catheter systems including any number of lightguides for generating pressure waves within an inflatable balloon(sometimes referred to herein simply as “balloon”) for disruptingintervascular lesions. The catheter systems herein can utilize lightenergy to generate a plasma near the light guide disposed in theinflatable balloon located at or near a treatment site. As used herein,the treatment site can include a vascular lesion such as a calcifiedvascular lesion or a fibrous vascular lesion (hereinafter sometimesreferred to simply as a “lesion”), typically found in a blood vesseland/or a heart valve. The plasma formation can initiate a pressure waveand can initiate the rapid formation of one or more bubbles that canrapidly expand to a maximum size and then dissipate through a cavitationevent that can also launch a pressure wave upon collapse. The rapidexpansion of the plasma-induced bubbles can generate one or morepressure waves within a balloon fluid and thereby impart pressure wavesupon the treatment site. The pressure waves can transfer mechanicalenergy through an incompressible balloon fluid to a treatment site toimpart a fracture force on the lesion. Without wishing to be bound byany particular theory, it is believed that the rapid change in balloonfluid momentum upon a balloon wall of the inflatable balloon that is incontact with or positioned near the lesion is transferred to the lesionto induce fractures in the lesion.

The catheter systems can include a catheter configured to advance to thelesion located within or adjacent to the blood vessel, where thecatheters include a catheter shaft. The catheters also include one ormore light guides disposed along the catheter shaft and within aballoon. Each light guide can be configured to be in opticalcommunication with a light and/or power source.

Those of ordinary skill in the art will realize that the followingdetailed description of the present invention is illustrative only andis not intended to be in any way limiting. Other embodiments of thepresent invention will readily suggest themselves to such skilledpersons having the benefit of this disclosure. Additionally, othermethods of delivering energy to the lesion can be utilized, including,but not limited to electric current induced plasma generation. Referencewill now be made in detail to implementations of the present inventionas illustrated in the accompanying drawings.

In the interest of clarity, not all of the routine features of theimplementations described herein are shown and described. It will, ofcourse, be appreciated that in the development of any such actualimplementation, numerous implementation-specific decisions must be madein order to achieve the developer's specific goals, such as compliancewith application-related and business-related constraints, and thatthese specific goals will vary from one implementation to another andfrom one developer to another. Moreover, it is appreciated that such adevelopment effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking of engineering for those ofordinary skill in the art having the benefit of this disclosure.

As an overview, in certain embodiments, the light guides can beconfigured to include one or more diverting features configured todirect light to exit from the light guide toward a side surface of thelight guide and toward the balloon wall. The diverting features candirect light to exit in a direction away from the axis of the lightguide, or in an off-axis direction. Additionally, or in the alternative,the light guides can each include one or more light windows disposedalong the longitudinal or axial surfaces of each light guide and inoptical communication with a diverting feature. The light windows caninclude a portion of the light guide that allows light to exit the lightguide from within the light guide, such as a portion of the light guidelacking a cladding material on or about the light guide. The inflatableballoons described herein can be coupled to the catheter shaft and/orother structures, and can be inflated with a balloon fluid.

The inflatable balloon can include a balloon wall and can be configuredto expand from a deflated state suitable for advancing the catheterthrough a patient's vasculature to an inflated state suitable foranchoring the catheter in position relative to a treatment site. Thepower source can be configured to provide sub-millisecond pulses of alight from the power source to initiate plasma formation in a balloonfluid within the balloon to cause rapid bubble formation and to impartpressure waves upon the treatment site.

Various embodiments of this invention shine laser light energy onto aplasma target to cause plasma generation via interaction with plasmatarget material rather than optical breakdown of the balloon fluidthereby moving the plasma creation away from a distal end of the opticalfiber (light guide). This can be accomplished by positioning the plasmatarget away from the distal end of the optical fiber to absorb the lightenergy and convert it into a plasma at some distance away from thedistal end of the light guide.

As used herein, the terms “intravascular lesion” and “vascular lesion”are used interchangeably unless otherwise noted.

It is appreciated that the catheter systems herein can include manydifferent forms. Referring now to FIG. 1 , a schematic cross-sectionalview is shown of a catheter system in accordance with variousembodiments herein. A catheter system 100 is suitable for impartingpressure to induce fractures in a vascular lesion within or adjacent avessel wall of a blood vessel. In the embodiment illustrated in FIG. 1 ,the catheter system 100 can include one or more of a catheter 102, oneor more light guides 122, a power source 124, a manifold 136 and a fluidpump 138.

The catheter 102 includes an inflatable balloon 104 (sometimes referredto herein as “balloon”). The catheter 102 is configured to move to atreatment site 106 within or adjacent to a blood vessel 108. Thetreatment site 106 can include a vascular lesion such as a calcifiedvascular lesion, for example. Additionally, or in the alternative, thetreatment site 106 can include a vascular lesion such as a fibrousvascular lesion.

The catheter 102 can include the balloon 104, a catheter shaft 110 and aguidewire 112. The balloon can be coupled to the catheter shaft 110. Theballoon can include a balloon proximal end 104P and a balloon distal end104D. The catheter shaft 110 can extend between a shaft proximal end 114and a shaft distal end 116. The catheter shaft 110 can include aguidewire lumen 118 which is configured to move over the guidewire 112.The catheter shaft 110 can also include an inflation lumen (not shown).In some embodiments, the catheter 102 can have a distal end opening 120and can accommodate and be moved over and/or along the guidewire 112 sothat the balloon 104 is positioned at or near the treatment site 106.

The catheter shaft 110 of the catheter 102 can encircle one or morelight guides 122 (only one light guide 122 is illustrated in FIG. 1 forclarity) in optical communication with a power source 124. The lightguide 122 can be at least partially disposed along and/or within thecatheter shaft 110 and at least partially within the balloon 104. Invarious embodiments, the light guide 122 can be an optical fiber and thepower source 124 can be a laser. The power source 124 can be in opticalcommunication with the light guide 122. In some embodiments, thecatheter shaft 110 can encircle multiple light guides such as a secondlight guide, a third light guide, etc.

The balloon 104 can include a balloon wall 130. The balloon 104 canexpand from a collapsed configuration suitable for advancing at least aportion of the catheter shaft 102 through a patient's vasculature to anexpanded configuration suitable for anchoring the catheter 102 intoposition relative to the treatment site 106. The power source 124 of thecatheter system 100 can be configured to provide sub-millisecond pulsesof light from the power source 124, along the light guide 112, to alocation within the balloon 104. The pulses of light, resulting in lightenergy, thereby induce plasma formation in a balloon fluid 132 withinthe balloon 104. The plasma formation causes rapid bubble formation, andimparts pressure waves upon the treatment site 106. Exemplaryplasma-induced bubbles are shown as bubbles 134 in FIG. 1 . The balloonfluid 132 can be a liquid or a gas. As provided in greater detailherein, the plasma-induced bubbles 134 are intentionally formed at somedistance away from the light guide 122 so that the likelihood of damageto the light guide is decreased.

In various embodiments, the sub-millisecond pulses of light can bedelivered to near the treatment site 106 at a frequency of from at leastapproximately 1 hertz (Hz) up to approximately 5000 Hz. In someembodiments, the sub-millisecond pulses of light can be delivered tonear the treatment site 106 at a frequency from at least 30 Hz to 1000Hz. In other embodiments, the sub-millisecond pulses of light can bedelivered to near the treatment site 106 at a frequency from at least 10Hz to 100 Hz. In yet other embodiments, the sub-millisecond pulses oflight can be delivered to near the treatment site 106 at a frequencyfrom at least 1 Hz to 30 Hz. In some embodiments, the sub-millisecondpulses of light can be delivered to near the treatment site 106 at afrequency that can be greater than or equal to 1 Hz, 2 Hz, 3 Hz, 4 Hz, 5Hz, 6 Hz, 7 Hz, 8 Hz, or 9 Hz, 10 Hz, 20 Hz, 30 Hz, 40 Hz, 50 Hz, 60 Hz,70 Hz, 80 Hz, 90 Hz, 100 Hz, 200 Hz, 300 Hz, 400 Hz, 500 Hz, 600 Hz, 700Hz, 800 Hz, 900 Hz, 1000 Hz, 1250 Hz, 1500 Hz, 1750 Hz, 2000 Hz, 2250Hz, 2500 Hz, 2750 Hz, 3000 Hz, 3250 Hz, 3500 Hz, 3750 Hz, 4000 Hz, 4250Hz, 4500 Hz, 4750 Hz, or 5000 Hz or can be an amount falling within arange between any of the foregoing. Alternatively, the sub-millisecondpulses of light can be delivered to near the treatment site 106 at afrequency that can be greater than 5000 Hz.

It is appreciated that the catheter system 100 herein can include anynumber of light guides 122 in optical communication with the powersource 124 at the proximal portion 114, and with the balloon fluid 132within the balloon 104 at the distal portion 116. For example, in someembodiments, the catheter system 100 herein can include from one lightguide 122 to five light guides 122. In other embodiments, the cathetersystem 100 herein can include from five light guides to fifteen lightguides. In yet other embodiments, the catheter system 100 herein caninclude from ten light guides to thirty light guides. The cathetersystem 100 herein can include 1-30 light guides. It is appreciated thatthe catheter system 100 herein can include any number of light guidesthat can fall within a range, wherein any of the forgoing numbers canserve as the lower or upper bound of the range, provided that the lowerbound of the range is a value less than the upper bound of the range. Insome embodiments, the catheter system 100 herein can include greaterthan 30 light guides.

The manifold 136 can be positioned at or near the shaft proximal end114. The manifold 136 can include one or more proximal end openings thatcan receive the one or more light guides, such as light guide 122, theguidewire 112, and/or an inflation conduit 140. The catheter system 100can also include the fluid pump 138 that is configured to inflate theballoon 104 with the balloon fluid 132 and/or deflate the balloon 104 asneeded.

As with all embodiments illustrated and described herein, variousstructures may be omitted from the figures for clarity and ease ofunderstanding. Further, the figures may include certain structures thatcan be omitted without deviating from the intent and scope of theinvention.

FIG. 2 is a simplified schematic side view of one embodiment of aportion of the catheter system 200, including one embodiment of aportion of a catheter 202. In the embodiment illustrated in FIG. 2 , thecatheter system can include one or more of an inflatable balloon 204, aguidewire lumen 218 and a light guide 222. Although the light guide 222in FIG. 2 (as well as other embodiments shown and/or described herein)is illustrated as being positioned adjacent to the guidewire lumen 218,it is understood that in some embodiments, the light guide 222 can bepositioned within the guidewire lumen 218 or the catheter shaft 110(illustrated in FIG. 1 ), or the light guide 222 can be incorporatedinto a portion of the guidewire lumen 218 or the catheter shaft 110. Instill other embodiments, the light guide 222 can be positioned away fromthe guidewire lumen 218 and/or the catheter shaft 110. In yet otherembodiments, the guidewire lumen 218 can be omitted from the cathetersystem 200. It is further recognized that the structures included inFIG. 2 (as well as other figures shown and described herein) are notnecessarily drawn to scale for ease of viewing and/or understanding.

In the embodiment illustrated in FIG. 2 , the catheter system 200 alsoincludes a plasma target 242 that is spaced apart from the distal tip244 of the light guide 222. The plasma target 242 can be formed fromvarious materials. In some embodiments, the plasma target 242 can beformed from metallics and/or metal alloys having relatively high meltingtemperatures, such as tungsten, tantalum, molybdenum, niobium, platinumand/or iridium. Alternatively, the plasma target 242 can be formed fromat least one of magnesium oxide, beryllium oxide, tungsten carbide,titanium nitride, titanium carbonitride and titanium carbide. Stillalternatively, the plasma target 242 can be formed from at least one ofdiamond CVD and diamond. In other embodiments, the plasma target 242 canbe formed from transition metal, an alloy metal or a ceramic material.Still alternatively, the plasma target 242 can be formed from any othersuitable material(s). As provided in greater detail herein, thegeometry, configuration, size and/or shape of the plasma target 242 canalso be varied to suit the design requirements of the catheter system200.

In the embodiment illustrated in FIG. 2 , the light guide 222 emitslight energy 243 (illustrated in dashed lines in FIG. 2 ) from a distaltip 244 of the light guide 222 toward the plasma target 242. The plasmatarget 242 is spaced apart from the distal tip 244 of the light guide bya target gap distance 245. The target gap distance 245 can vary. Forexample, in various embodiments, the target gap distance 245 can be atleast 1 μm, at least 10 μm, at least 100 μm, at least 1 mm, at least 2mm, at least 3 mm, at least 5 mm or at least 1 cm. The target gapdistance 245 can vary depending upon the size, shape and/or angle of theplasma target 242 relative to the light energy emitted by the lightguide 222, the type of material used to form the plasma target 242, thequantity and/or duration of the light energy being emitted from thelight guide 222, the type of balloon fluid 232 used in the balloon 204,etc.

In certain embodiments, the plasma target 242 can be secured to anotherstructure of the catheter system 200. For example, the plasma target 242can be fixedly or movably secured or coupled to the guidewire lumen 218,as illustrated in FIG. 2 . Alternatively, the plasma target 242 can befixedly or movably secured or coupled to the light guide 222 or anothersuitable structure. Still alternatively, the plasma target 242 can besuspended (unsecured) within the balloon fluid 232.

With this design, the light energy 243 generates a plasma bubble 234,which creates an outwardly emanating pressure wave (not shown)throughout the balloon fluid 232 that impacts the balloon 204. Theimpact to the balloon 204 causes the balloon to forcefully disruptand/or fracture the vascular lesion, e.g. a calcified vascular lesion,at the treatment site 106 (illustrated in FIG. 1 ). In other words, theassociated rapid formation of the plasma bubble 234 and resultinglocalized balloon fluid 232 velocity within the balloon 204 transfersmechanical energy though the incompressible balloon fluid 232 to imparta fracture force on the treatment site 106. The rapid change in momentumof the balloon fluid 232 upon hitting the balloon wall 230 is known ashydraulic shock, or water hammer. The change in momentum of the balloonfluid 232 is transferred as a fracture force to the vascular lesionwhich is opposed to the balloon wall 230.

By positioning the plasma target 242 away from the distal tip 244 of thelight guide 222, damage to the light guide 222 from the plasma bubble234 is less likely to occur than if the plasma bubble 234 was generatedat or more proximate the distal tip 244 of the light guide. Statedanother way, the presence of the plasma target 242, and positioning theplasma target 242 away from the distal tip 244 of the light guide 222,causes the plasma bubble 234 to in turn be generated away from thedistal tip 244 of the light guide 222, reducing the likelihood of damageto the light guide 222. Further, in this embodiment, the positioning ofthe plasma target 242 can also be different from those previouslydescribed.

FIG. 3A is a simplified schematic side view of another embodiment of aportion of the catheter system 300, including another embodiment of aportion of the catheter 302, shown in an inflated state. In thisembodiment, the catheter 302 includes a balloon 304, a guidewire lumen318, one or more light guides 322 (two light guides 322 are illustratedin FIG. 3A) and one or more plasma targets 342 (two plasma targets 342are illustrated in FIG. 3A). In the embodiment illustrated in FIG. 3A,the light guides 322 can be substantially similar to the light guidespreviously shown and described herein and/or shown in greater detailbelow.

However, in this embodiment, the plasma targets 342 can be movabledepending upon the inflation status of the balloon 304. For example, theplasma targets 342 can include springs, e.g. can be spring-loaded, thatextend outwardly toward the balloon 304 when the balloon 304 is in theinflated state. Stated another way, the plasma targets 342 can moveand/or extend toward the balloon 304 (or in another suitable direction)so that the light energy 343 from the light guide(s) 322 is betterdirected toward the plasma target(s) 342. As previously describedherein, because the plasma target 342 is positioned away from the distaltip 344 of the light guide 322, the plasma bubble 334 that is generatedis less likely to cause damage to the light guide than if the plasmabubble 334 were generated at or more near to the light guide 322.

Further, in this embodiment, the positioning of the plasma targets 342can be staggered (with two or more plasma targets 342) so that a greaterarea of the balloon 304 can be impacted by the resultant pressurewave(s) from the plasma bubbles 334.

FIG. 3B is a simplified schematic side view of the portion of thecatheter illustrated in FIG. 3A, shown in a deflated state. In thisembodiment, upon deflation of the balloon 304, the plasma targets 342can retract or otherwise move back toward the guidewire lumen 318, or inanother suitable direction, so that the catheter 302 can have a somewhatsmaller diameter during insertion and/or removal of the catheter 302from the blood vessel 108 (illustrated in FIG. 1 ), thereby increasingthe ease of insertion and/or removal by the operator of the cathetersystem 300.

FIG. 4 is a simplified schematic side view of another embodiment of aportion of the catheter system 400, including another embodiment of aportion of the catheter 402. In the embodiment illustrated in FIG. 4 ,the catheter 402 includes a balloon 404, a guidewire lumen 418, one ormore light guides 422 and one or more plasma targets 442.

The operation and function of the light guide 422 and the plasma target442 can be substantially similar to those previously described. However,in this embodiment, the light guide 422 can be configured to redirectthe light energy 443 in a different direction, i.e. non-parallel with alongitudinal axis 470 of the light guide 422. For example, the lightenergy can be redirected at an angle α relative to the longitudinal axis470 of the light guide 422. In the embodiment illustrated in FIG. 4 ,the light energy 443 is redirected in a direction that is somewhatperpendicular to the longitudinal axis 470 of the light guide 422.However, it is understood that this type of angle is provided for easeof understanding only, and that any angle α between 0 and 180 degreesrelative to the longitudinal axis 470 of the light guide 422 can beused. The structures and methods for redirecting the light energy 443 inthis manner are provided in greater detail herein.

Further, in this embodiment, the positioning of the plasma target 442can also be different from those previously described. For example, inone embodiment, the plasma target 442 is positioned between the lightguide 422 and the balloon 404. In various embodiments, the plasma target442 can be secured or coupled to another structure within the catheter402, such as the guidewire lumen 418, the light guide 422, the balloon404, or any other suitable structure. With this design, the plasmabubble 434 can be generated more proximate to the balloon 404, which canbe beneficial for exerting a greater force to disrupt and/or fracturethe calcified lesion and/or to maintain a spacing between the formationof the plasma bubble 434 and the light guide 422 for reasons providedherein.

FIG. 5 is a simplified cross-sectional view of another embodiment of aportion of the catheter system 500, including another embodiment of aportion of the catheter 502. In the embodiment illustrated in FIG. 5 ,the balloon has been omitted for clarity. In this embodiment, thecatheter 502 includes a guidewire lumen 518, one or more light guides522, one or more plasma targets 542 and a target coupler 571.

The operation and function of the light guide 522 and the plasma target542 can be substantially similar to those previously described. However,in this embodiment, the plasma target 542 is coupled to the guidewirelumen 518 (or another suitable structure) with the target coupler 571.In one embodiment, the target coupler 571 can be a ring-like structurethat secures the plasma target 542 to the guidewire lumen 518 (oranother structure). The light energy 543 is emitted from the light guide522, and results in a plasma bubble 534 being generated at the plasmatarget 542. Alternatively, the plasma target 542 can be adhered directlyto the guidewire lumen 518 (or another structure) with adhesive or anyother means for securing the plasma target 542. Still alternatively, thetarget coupler 571 can be movable so that the plasma target 542 can bemoved either manually or automatically along the guidewire lumen 518 tochange the target gap distance 545 between the plasma target 542 and thedistal tip 544 of the light guide 522.

Additionally, or in the alternative, the shape of the plasma target 542can vary. For example, in the embodiment illustrated in FIG. 5 , theplasma target 542 can have a somewhat dome-shape or convexconfiguration. Still alternatively, the plasma target 542 can haveanother suitable configuration. With these designs, the plasma bubble534 can be generated at the plasma target 542, and the plasma target 542can redirect the resultant pressure wave in any desired direction toachieve the desired results.

FIG. 6 is a simplified schematic side view of another embodiment of aportion of the catheter system 600, including another embodiment of aportion of the catheter 602. In the embodiment illustrated in FIG. 6 ,the catheter 602 includes a balloon 604, a guidewire lumen 618, one ormore light guides 622 and one or more plasma targets 642.

The operation and function of the light guide 622 and the plasma target642 can be substantially similar to those previously described. However,in this embodiment, the plasma target 642 is secured to a balloon innersurface 672 of the balloon 604. With this design, the plasma bubble isgenerated away from the light guide 622, thereby decreasing thelikelihood of damage to the light guide 622. Moreover, because theplasma target 642 is positioned on the balloon inner surface 672, theballoon will receive a near-direct force from the plasma bubble 634 toincrease the disruptive force upon the calcified lesion.

In this embodiment, the light guide 622 can be configured to redirectthe light energy 643 in a different direction, i.e. non-parallel with alongitudinal axis 670 of the light guide 622. For example, the lightenergy can be redirected at an angle α relative to the longitudinal axis670 of the light guide 622. In the embodiment illustrated in FIG. 6 ,the light energy 643 is redirected in a direction that is somewhatperpendicular to the longitudinal axis 670 of the light guide 622.However, it is understood that this type of angle is provided for easeof understanding only, and that any angle α between 0 and 180 degreesrelative to the longitudinal axis 670 of the light guide 622 can beused. The structures and methods for redirecting the light energy 643 inthis manner are provided in greater detail herein.

Further, in this embodiment, the positioning of the plasma target 642can also be different from those previously described. For example, inone embodiment, the plasma target 642 is positioned between the lightguide 622 and the balloon 604. In various embodiments, the plasma target642 can be secured or coupled to another structure within the catheter602, such as the guidewire lumen 618, the light guide 622, the balloon604, or any other suitable structure. With this design, the plasmabubble 634 can be generated more proximate to the balloon 604, which canbe beneficial for exerting a greater force to disrupt and/or fracturethe calcified lesion and/or to maintain a spacing between the formationof the plasma bubble 634 and the light guide 622 for reasons providedherein.

FIG. 7A is a simplified schematic side view of another embodiment of aportion of the catheter system 700A, including another embodiment of aportion of the catheter 702A. In the embodiment illustrated in FIG. 7A,the catheter 702A includes a balloon 704, a guidewire lumen 718, one ormore light guides 722A and a plurality of plasma targets 742.

The operation and function of the light guide 722A and the plasmatargets 742 can be substantially similar to those previously described.However, in this embodiment, the light guide 722A can be configured todirect the light energy 743A parallel with a longitudinal axis 770 ofthe light guide 722B to generate plasma bubbles 734A at a plurality ofplasma targets 742. In this embodiment, the plasma targets 742 aredistributed throughout the balloon fluid 732 (illustrated as “X”'s inFIG. 7A). In this embodiment, the plasma targets 742 can be relativelysmall so that they can be suspended in the balloon fluid 732 morereadily. In various embodiments, the plasma targets 742 can befree-floating within the balloon fluid 732, either as a homogeneoussolution or a heterogeneous solution. With this design, one or moreplasma bubbles 734A (only one plasma bubble 734A is illustrated in FIG.7A) can be generated, which can be beneficial for exerting a greaterforce to disrupt and/or fracture the calcified lesion and/or to maintaina spacing between the formation of the plasma bubble 734A and the lightguide 722A for reasons provided herein.

FIG. 7B is a simplified schematic side view of another embodiment of aportion of the catheter system 700B, including another embodiment of aportion of the catheter 702B. In the embodiment illustrated in FIG. 7B,the catheter 702B includes a balloon 704, a guidewire lumen 718, one ormore light guides 722B and a plurality of plasma targets 742.

The operation and function of the light guide 722B and the plasmatargets 742 can be substantially similar to those previously described.However, in this embodiment, the light guide 722B can be configured toredirect the light energy 743B in a different direction, i.e.non-parallel with a longitudinal axis 770 of the light guide 722B. Forexample, the light energy 743B can be redirected at an angle α relativeto the longitudinal axis 770 of the light guide 722B. In the embodimentillustrated in FIG. 7B, the light energy 743B is redirected in adirection that is somewhat perpendicular or orthogonal to thelongitudinal axis 770 of the light guide 722B. However, it is understoodthat this type of angle is provided for ease of understanding only, andthat any angle α between 0 and 180 degrees relative to the longitudinalaxis 770 of the light guide 722B can be used. The structures and methodsfor redirecting the light energy 743B in this manner are provided ingreater detail herein.

Further, in this embodiment, the positioning of the plasma targets 742can also be different from those previously described. For example, inone embodiment, the plasma targets 742 are distributed throughout theballoon fluid 732 (illustrated as “X”'s in FIG. 7B). In this embodiment,the plasma targets 742 can be relatively small so that they can besuspended in the balloon fluid 732 more readily. In various embodiments,the plasma targets 742 can be free-floating within the balloon fluid732, either as a homogeneous solution or a heterogeneous solution. Withthis design, one or more plasma bubbles 734B (only one plasma bubble734B is illustrated in FIG. 7B) can be generated more proximate to theballoon 704, which can be beneficial for exerting a greater force todisrupt and/or fracture the calcified lesion and/or to maintain aspacing between the formation of the plasma bubble 734B and the lightguide 722B for reasons provided herein.

Examples of the catheters in accordance with the various embodimentsherein include those having multiple light guides disposed about thecatheter shaft at different positions around the circumference, as shownin FIGS. 8-11 . It is understood that multiple light guides can be usedwith any of the embodiments shown and/or described herein withoutdeviating from the intent and/or scope of the invention.

Referring now to FIG. 8 , a schematic cross-sectional view of a catheter102 in FIG. 1 along line 8-8 in FIG. 1 is shown in accordance withvarious embodiments herein. The catheter 802 illustrated in FIG. 8 caninclude one or more of a catheter shaft 810, a guidewire 812, aguidewire lumen 818, a first light guide 822A and a second light guide822B separated by about 180 degrees around the circumference from thefirst light guide 822A. The first light guide 822A includes a sidesurface that can include any surface portion about a circumference ofthe first light guide 822A. The second light guide 822B includes a sidesurface that can include any surface portion about the circumference ofthe second light guide 822B. In some embodiments, the side surface spansa portion of the circumference of the light guides herein, such that itis less than cylindrical. In other embodiments, the side surface canspan the entire circumference of the light guides herein such that it iscylindrical. It is recognized that any light guide described herein caninclude a side surface about the circumference of the light guide.

Referring now to FIGS. 9-11 , schematic cross-sectional views ofadditional configurations for catheters having multiple light guides areshown in accordance with various embodiments herein. The embodiment ofthe catheter 902 illustrated in FIG. 3 can include one or more of acatheter shaft 910, a guidewire 912, a guidewire lumen 918, a firstlight guide 922A, a second light guide 922B, and a third light guide922C separated by about 120 degrees around the circumference.

The embodiment of the catheter 1002 illustrated in FIG. 10 includes oneor more of a catheter shaft 1010, a guidewire 1012, a guidewire lumen1018, a first light guide 1022A, a second light guide 1022B, a thirdlight guide 1022C, and a fourth light guide 1022D separated by about 90degrees around the circumference.

The embodiment of the catheter 1102 illustrated in FIG. 11 includes oneor more of a catheter shaft 1110, a guidewire 1112, a guidewire lumen1118, a first light guide 1122A, a second light guide 1122B, a thirdlight guide 1122C, a fourth light guide 1122D, a fifth light guide1122E, and a sixth light guide 1122F separated by about 60 degreesaround the circumference. It is understood that greater than six lightguides can be used in the embodiments herein.

It is further appreciated that the light guides described herein can bedisposed uniformly or nonuniformly about the catheter shaft to achievethe desired effect in the desired locations.

Diverting features and focusing features (also sometimes referred toherein simply as “diverting features”) will be discussed in more detailbelow and in reference to FIGS. 12-15 . The light guides herein caninclude one or more diverting features, where each diverting feature canbe in optical communication with the light guide within which it isdisposed. In some embodiments, the diverting features can be in opticalcommunication with a distal end of the light guide. Referring now toFIGS. 12-15 , schematic cross-sectional views of the distal ends ofvarious shaped light guides are shown in accordance with variousembodiments herein.

In FIG. 12 , a schematic cross-sectional view of a light guide 1222 isshown. Light guide 1222 is configured such that light 1254 travels fromthe power source 124 (illustrated in FIG. 1 ) in a direction from theshaft proximal end 114 (illustrated in FIG. 1 ) to the distal tip 1244,as indicated by arrows 1254.

In some embodiments, the end of the light guide can have an angledshape. By way of example, in FIG. 13 a schematic cross-sectional view ofa light guide 1322 is shown.

In some embodiments, the end of the light guide can have a taperedshape. By way of example, in FIG. 14 a schematic cross-sectional view ofa light guide 1422 is shown.

Referring now to FIG. 15 , a schematic cross-sectional view of a lightguide 1522 is shown. Light guide 1522 includes an angled end 1558disposed on a side surface 1562 of a distal end 1564 of the light guide1522. The light guide 1522 includes a diverting feature 1566 at thedistal tip 1544 to direct the light energy 1554 within the light guide1522 toward the side surface 1562 of the light guide 1522. Light guide1522 is configured such that light energy 1554 travels from the distaltip 1544 in a direction that is approximately 90 degrees (or anothersuitable angle) from the longitudinal axis 470 (illustrated in FIG. 4 ,for example) as indicated by arrows 1568. Upon contact with thediverting feature 1566, the light energy 1554 is diverted, or reflected,within the light guide 1522 to a side surface 1562 of the light guide1522. The light energy 1554 extends away from the side surface 1562 ofthe light guide 1522.

The diverting feature 1566 of light guide 1522 can be made from areflecting element or a refracting element. The diverting feature 1566can be made from a glass, a polymer, a mirror, or a reflective metalcoating. It is appreciated that the angle of internal reflection by thediverting feature 1566 can be adjusted by changing the angle of thedistal tip 1544 of light guide 1522.

In some embodiments, a diverting feature can be included with the lightguide to direct light toward a side surface of the distal end of thelight guide. A diverting feature can include any feature of the systemherein that diverts light from the light guide away from its axial pathtoward a side surface of the light guide. Examples include a reflector,a refracting structure, and a fiber diffuser.

In some embodiments herein, the light guides can include multiplediverting features. By way of example, each light guide herein caninclude a first diverting feature, a second diverting feature, a thirddiverting feature or a fourth diverting feature. In other embodiments,each light guide can include more than four diverting features. Thediverting features can be configured to direct light to exit a lightguide at a side surface thereof toward the balloon wall. In someexamples, the diverting feature directs light toward the balloon surfaceclosest to the diverting feature, so that the light does not cross thelongitudinal axis of the catheter on its path to the balloon surface. Itis appreciated that the diverting features can be in opticalcommunication with corresponding light window.

The diverting features herein can be configured to direct light in thelight guide toward a side surface of the distal portion, where the sidesurface is in optical communication with a light window. It isappreciated that the light guides herein can each include multiplediverting features and multiple light windows. Examples of the divertingfeatures suitable for use herein include a reflecting element, arefracting element and/or a fiber diffuser.

FIG. 16 is a simplified schematic side view of one embodiment of aportion of a catheter, including a light guide 1622 and an embodiment ofa portion of a plasma target 1642. The plasma target 1642 includes atarget face 1672. The target face 1672 can have any suitable geometry,shape or configuration. In this embodiment, the light guide 1622 and theplasma target 1642 operate substantially similar to those previouslyshown and/or described. However, in this embodiment, the target face1672 is angled relative to a longitudinal axis 1670 of the light guide1622. Stated another way, the target face 1672 has an angle α that canbe any angle between 0 and 180 degrees relative to the longitudinal axis1670 of the light guide 1622.

FIGS. 16A-16J are cross-sectional views showing representative,non-exclusive, non-limiting embodiments of the cross-sectional shape ofthe plasma target 1642. It is understood that there are literally aninfinite number of possible cross-sectional configurations for theplasma target 1642 and that it would be an impossibility to show anddescribe all such configurations. However, it is the intent that thescope of this invention would encompass all such potentialconfigurations, even those that are not shown and/or described herein.

FIG. 16A is a cross-sectional view of one embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially circular cross-sectional shape.

FIG. 16B is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially vertical oval or ellipticalcross-sectional shape.

FIG. 16C is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially square cross-sectional shape.

FIG. 16D is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially diamond, trapezoidal orparallelogram cross-sectional shape.

FIG. 16E is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially hexagonal cross-sectional shape.

FIG. 16F is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially horizontal oval or ellipticalcross-sectional shape.

FIG. 16G is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially pentagonal cross-sectional shape.

FIG. 16H is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially octagonal cross-sectional shape.

FIG. 16I is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially vertical rectangularcross-sectional shape.

FIG. 16J is a cross-sectional view of another embodiment of the plasmatarget 1642 taken on line 16-16 in FIG. 16 . In this embodiment theplasma target 1642 has a substantially horizontal rectangularcross-sectional shape.

FIGS. 17A-17H are perspective views showing representative,non-exclusive, non-limiting embodiments of the geometry, shape and/orconfiguration of the target face 1772A-H of the plasma target 1742A-H.It is understood that there are literally an infinite number of possiblecross-sectional configurations for the target face 1772A-H of the plasmatarget 1742A-H and that it would be an impossibility to show anddescribe all such configurations. However, it is the intent that thescope of this invention would encompass all such potentialconfigurations, even those that are not shown and/or described herein.

FIG. 17A is a perspective view of a portion of an embodiment of theplasma target 1742A having one embodiment of a target face 1772A. Inthis embodiment, the target face 1772A has a somewhat conicalconfiguration.

FIG. 17B is a perspective view of a portion of an embodiment of theplasma target 1742B having one embodiment of a target face 1772B. Inthis embodiment, the target face 1772B has a somewhat pyramidalconfiguration.

FIG. 17C is a perspective view of a portion of an embodiment of theplasma target 1742C having one embodiment of a target face 1772C. Inthis embodiment, the target face 1772C has a somewhat convex ordome-shaped configuration.

FIG. 17D is a perspective view of a portion of an embodiment of theplasma target 1742D having one embodiment of a target face 1772D. Inthis embodiment, the target face 1772D has a somewhat concaveconfiguration.

FIG. 17E is a perspective view of a portion of an embodiment of theplasma target 1742E having one embodiment of a target face 1772E. Inthis embodiment, the target face 1772E includes a spiral projection 1774that extends outwardly from a side portion 1776 of the plasma target1742E.

FIG. 17F is a perspective view of a portion of an embodiment of theplasma target 1742F having one embodiment of a target face 1772F. Inthis embodiment, the target face 1772F has a somewhat spring-like orcoiled configuration.

FIG. 17G is a perspective view of a portion of an embodiment of theplasma target 1742G having one embodiment of a target face 1772G. Inthis embodiment, the target face 1772G has a beveled configuration.

FIG. 17H is a perspective view of a portion of an embodiment of theplasma target 1742H having one embodiment of a target face 1772H. Inthis embodiment, the target face 1772H includes one or more surfacefeatures 1778. The surface features 1778 can include dimples,depressions or indentations that extend into a target surface 1780 ofthe target face 1772H. Additionally, or in the alternative, the surfacefeatures 1778 can include projections that extend outwardly from thetarget surface 1780 of the target face 1772H. In one embodiment, thesurface features 1778 can include the same or other materials that areadded to the target surface 1780. The specific sizes and/or shape(s) ofthe surface features 1778 can be varied.

FIG. 18 is a cross-sectional view of a portion of the catheter system1800 including one embodiment of a portion of the catheter 1802. In thisembodiment, the catheter 1802 can include a guidewire lumen 1818, one ormore light guides 1822 and an embodiment of a portion of a plasma target1842. The plasma target 1842 is spaced apart from the light guide 1822,and includes a target face 1872. The target face 1872 can have anysuitable geometry, shape or configuration. In this embodiment, the lightguide 1822 and the plasma target 1842 operate substantially similar tothose previously shown and/or described. However, in this embodiment,the plasma target 1842 can be annular and can encircle the circumferenceof the guidewire lumen 1818. Further, the target face 1872 of the plasmatarget 1842 can have a somewhat concave, conical configuration. Inalternative, non-exclusive embodiments, the plasma target 1842 can havea beveled, toroidal or frustoconical configuration, or any othersuitable configuration. In an alternative embodiment, the plasma target1842 only partially encircles the guidewire lumen 1818. Stillalternatively, the plasma target 1842 can encircle or partially encircleanother structure of the catheter 1802.

FIG. 19 is a cross-sectional view of a portion of the catheter system1900 including one embodiment of a portion of the catheter 1902. In thisembodiment, the catheter 1902 can include a guidewire lumen 1918, one ormore light guides 1922 and an embodiment of a portion of a plasma target1942. The plasma target 1942 is spaced apart from the light guide 1922,and includes a target face 1972. The target face 1972 can have anysuitable geometry, shape or configuration. In this embodiment, the lightguide 1922 and the plasma target 1942 operate substantially similar tothose previously shown and/or described. However, in this embodiment,the plasma target 1942 can be annular and can encircle the circumferenceof the guidewire lumen 1918. Further, the target face 1972 of the plasmatarget 1942 can have a somewhat conical or pyramidal configuration. Inan alternative embodiment, the plasma target 1942 only partiallyencircles the guidewire lumen 1918. Still alternatively, the plasmatarget 1942 can encircle or partially encircle another structure of thecatheter 1902.

FIG. 20 is a cross-sectional view of a portion of the catheter system2000 including one embodiment of a portion of the catheter 2002. In thisembodiment, the catheter 2002 can include a guidewire lumen 2018, two ormore light guides 2022 (only two light guides 2022 are illustrated inFIG. 20 ) and an embodiment of a portion of a plasma target 2042. Theplasma target 2042 is spaced apart from the light guides 2022, andincludes a target face 2072. The target face 2072 can have any suitablegeometry, shape or configuration. In this embodiment, the light guides2022 and the plasma target 2042 operate substantially similar to thosepreviously shown and/or described. In an alternative embodiment, two ormore plasma targets 2042 can be secured to the guidewire lumen 2018,wherein each only partially encircles the guidewire lumen 2018. Stillalternatively, the plasma target 2042 can encircle or partially encircleanother structure of the catheter 2002. It is appreciated that greaterthan two light guides 2022 can be used with the catheter system 2000herein. For example, three light guides 2022 can be evenly spaced apartby 120 degrees from one another; four light guides 2022 can be evenlyspaced apart by 90 degrees from one another, etc. Still alternatively,any number of light guides 2022 may be positioned so they are not evenlyspaced circumferentially around the guidewire lumen 2018.

FIG. 21 is a cross-sectional view of a portion of the catheter system2100 including one embodiment of a portion of the catheter 2102. In thisembodiment, the catheter 2102 can include a guidewire lumen 2118, two ormore light guides including a first light guide 2122F, and a secondlight guide 2122S (only two light guides are illustrated in FIG. 21 )and two or more plasma targets including a first plasma target 2142Fhaving a first target face 2172F, and a second plasma target 2142S (onlytwo plasma targets are illustrated in FIG. 21 ) having a second targetface 2172S. In the embodiment illustrated in FIG. 21 , the first lightguide 2122F emits light energy to generate a first plasma bubble 2134Fat or near the first target face 2172F of the first plasma target 2142F.The second light guide 2122S emits light energy to generate a secondplasma bubble 2134S at or near the second target face 2172S of thesecond plasma target 2142S, which is spaced apart from the first plasmatarget 2142F. In the embodiment illustrated in FIG. 21 , the secondlight guide 2122S extends through the first plasma target 2142F.Alternatively, the second light guide 2122S can traverse around thefirst plasma target 2142F. Still alternatively, any or all of the plasmatargets 2142F, 2142S can either encircle the guidewire lumen 2118, orpartially encircle the guidewire lumen 2118.

Balloons

The balloons suitable for use in the catheter systems illustrated and/ordescribed herein include those that can be passed through thevasculature of a patient when in a collapsed configuration. In someembodiments, the balloons illustrated and/or described herein are madefrom silicone. In other embodiments, the balloons herein are made frompolydimethylsiloxane (PDMS), polyurethane, polymers such as PEBAX™material available from Arkema, which has a location at King of Prussia,Pa., USA, nylon, and the like. In some embodiments, the balloons caninclude those having diameters ranging from 1 millimeter (mm) to 25 mmin diameter. In some embodiments, the balloons can include those havingdiameters ranging from at least 1.5 mm to 12 mm in diameter. In someembodiments, the balloons can include those having diameters rangingfrom at least 1 mm to 5 mm in diameter. In some embodiments, thediameter can be greater than or equal to 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm,2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm,7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, 10.0 mm, 10.5 mm, 11.0mm, 11.5 mm, 12.0 mm, 12.5 mm, 13.0 mm, 13.5 mm, 14.0 mm, 14.5 mm, 15.0mm, 15.5 mm, 16.0 mm, 16.5 mm, 17.0 mm, 17.5 mm, 18.0 mm, 18.5 mm, 19.0mm, 19.5 mm, or 20.0 mm, or can be an amount falling within a rangebetween any of the foregoing.

In some embodiments, the balloons illustrated and/or described hereincan include those having a length ranging from at least 5 mm to 300 mmin length. In some embodiments, the balloons illustrated and/ordescribed herein can include those having a length ranging from at least8 mm to 200 mm in length. In some embodiments, the length of the ballooncan be greater than or equal to 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm,60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm, 230 mm, 240mm, 250 mm, 260 mm, 270 mm, 280 mm, 290 mm, or 300 mm, or can be anamount falling within a range between any of the foregoing.

The balloons illustrated and/or described herein can be inflated toinflation pressures from 1 atmosphere (atm) to 70 atm. In someembodiments, the balloons illustrated and/or described herein can beinflated to inflation pressures of from at least 20 atm to 70 atm. Insome embodiments, the balloons illustrated and/or described herein canbe inflated to inflation pressures of from at least 6 atm to 20 atm. Insome embodiments, the balloons illustrated and/or described herein canbe inflated to inflation pressures of from at least 3 atm to 20 atm. Insome embodiments, the balloons illustrated and/or described herein canbe inflated to inflation pressures of from at least 2 atm to 10 atm. Insome embodiments, the balloons illustrated and/or described herein canbe inflated to inflation pressures that can be greater than or equal to1 atm, 2 atm, 3 atm, 4 atm, 5 atm, 6 atm, 7 atm, 8 atm, 9 atm, 10 atm,15 atm, 20 atm, 25 atm, 30 atm, 35 atm, 40 atm, 45 atm, 50 atm, 55 atm,60 atm, 65 atm, or 70 atm, or can be an amount falling within a rangebetween any of the foregoing.

The balloons illustrated and/or described herein can include thosehaving various shapes, including, but not to be limited to, a conicalshape, a square shape, a rectangular shape, a spherical shape, aconical/square shape, a conical/spherical shape, an extended sphericalshape, an oval shape, a tapered, shape, a bone shape, a stepped diametershape, an offset shape, or a conical offset shape. In some embodiments,the balloons illustrated and/or described herein can include a drugeluting coating or a drug eluting stent structure. The drug elutioncoating or drug eluting stent can include one or more therapeutic agentsincluding anti-inflammatory agents, anti-neoplastic agents,anti-angiogenic agents, and the like.

Balloon Fluids

Exemplary balloon fluids suitable for use herein can include, but arenot to be limited to one or more of water, saline, contrast medium,fluorocarbons, perfluorocarbons, gases, such as carbon dioxide, and thelike. In some embodiments, the balloon fluids illustrated and/ordescribed herein can be used as base inflation fluids, discussedelsewhere herein. In some embodiments, the balloon inflation fluidsinclude a mixture of saline to contrast medium in a volume ratio of50:50. In some embodiments, the balloon fluids include a mixture ofsaline to contrast medium in a volume ratio of 25:75. In someembodiments, the balloon fluids include a mixture of saline to contrastmedium in a volume ratio of 75:25. The balloon fluids suitable for useherein can be tailored on the basis of composition, viscosity, and thelike in order to manipulate the rate of travel of the pressure wavestherein. The balloon fluids suitable for use herein are biocompatible. Avolume of balloon fluid can be tailored by the chosen power source andthe type of balloon fluid used.

In some embodiments, the contrast agents used in the contrast mediaherein can include, but are not to be limited to, iodine-based contrastagents, such as ionic or non-ionic iodine-based contrast agents. Somenon-limiting examples of ionic iodine-based contrast agents includediatrizoate, metrizoate, iothalamate, and ioxaglate. Some non-limitingexamples of non-ionic iodine-based contrast agents include iopamidol,iohexol, ioxilan, iopromide, iodixanol, and ioversol. In otherembodiments, non-iodine based contrast agents can be used. Suitablenon-iodine containing contrast agents can include gadolinium (III)-basedcontrast agents. Suitable fluorocarbon and perfluorocarbon agents caninclude, but are not to be limited to, agents such as theperfluorocarbon dodecafluoropentane (DDFP, C5F12).

The balloon fluids illustrated and/or described herein can include thosethat include absorptive agents that can selectively absorb light in theultraviolet (e.g., at least 10 nanometers (nm) to 400 nm), visibleregion (e.g., at least 400 nm to 780 nm), and near-infrared region ofthe electromagnetic spectrum (e.g., at least 780 nm to 2.5 μm), or inthe far-infrared region of the electromagnetic spectrum of at least 10nm to 2.5 micrometers (μm). Suitable absorptive agents can include thosewith absorption maxima along the spectrum from at least 10 nm to 2.5 μm.In various embodiments, the absorptive agent can be those that have anabsorption maximum matched with the emission maximum of the laser usedin the catheter system. By way of non-limiting examples, various lasersdescribed herein can include neodymium:yttrium-aluminum-garnet(Nd:YAG−emission maximum=1064 nm) lasers. holmium:YAG (Ho:YAG−emissionmaximum=2.1 μm) lasers, or erbium:YAG (Er:YAG−emission maximum=2.94 μm).In some embodiments, the absorptive agents used herein can be watersoluble. In other embodiments, the absorptive agents used herein are notwater soluble. In some embodiments, the absorptive agents used in theballoon fluids herein can be tailored to match the peak emission of thepower source. Various power sources having emission wavelengths of atleast 10 nanometers to 1 millimeter are discussed elsewhere herein.

In some embodiments, introduction of the balloon fluid causes theexpansion of the balloon from a collapsed configuration to a firstexpanded configuration and from a first expanded configuration to asecond further expanded configuration. In addition, or alternatively,the expansion of the balloon can be accomplished using a shape-memorymaterial or other means.

Light Guides

The light guides illustrated and/or described herein can include anoptical fiber or flexible light pipe. The light guides illustratedand/or described herein can be thin and flexible and can allow lightsignals to be sent with very little loss of strength. The light guidesillustrated and/or described herein can include a core surrounded by acladding about its circumference. In some embodiments, the core can be acylindrical core or a partially cylindrical core. The core and claddingof the light guides can be formed from one or more materials, includingbut not limited to one or more types of glass, silica, or one or morepolymers. The light guides may also include a protective coating, suchas a polymer. It is appreciated that the index of refraction of the corewill be greater than the index of refraction of the cladding.

Each light guide can guide light along its length to a distal portionhaving at least one optical window. The light guides can create a lightpath as portion of an optical network including a power source. Thelight path within the optical network allows light to travel from onepart of the network to another. Both the optical fiber or the flexiblelight pipe can provide a light path within the optical networks herein.

The light guides illustrated and/or described herein can assume manyconfigurations about the catheter shaft of the catheters illustratedand/or described herein. In some embodiments, the light guides can runparallel to the longitudinal axis of the catheter shaft of the catheter.In some embodiments, the light guides can be disposed spirally orhelically about the longitudinal axis of the catheter shaft of thecatheter. In some embodiments, the light guides can be physicallycoupled to the catheter shaft. In other embodiments, the light guidescan be disposed along the length of the outer diameter of the cathetershaft. In yet other embodiments the light guides herein can be disposedwithin one or more light guide lumens within the catheter shaft. Variousconfigurations for the catheter shafts and light guide lumens will bediscussed below.

Diverting Features and Focusing Features

The diverting features suitable for use herein include a reflectingelement, a refracting element, and a fiber diffuser. In someembodiments, the diverting feature can be a reflecting element. In someembodiments, the diverting feature can be a refracting element. In someembodiments, the diverting feature can be a fiber diffuser.

A fiber diffuser can direct light from within a light guide to exit at aside surface of the light guide. The fiber diffusers described hereincan be created several ways. In some embodiments, the fiber diffuserscan be created by micro-machining the surface of the distal portion of alight guide with a CO₂ laser. In some embodiments, a fused silicacoating can be applied to the distal portion of the light guide. Inother embodiments, the fiber diffuser can be formed from a glass, apolymer, or a metal coating on the distal portion of the light guide. Inother embodiments, the fiber diffuser can be formed by a fiber Bragggrating on the distal portion of the light guide. In some embodiments,the fiber diffuser can include a machined portion of the light guide, alaser-machined portion of the light guide, fiber Bragg gratings, a fusedsplicing, a fused splicing forming at least one internal mirror, and asplicing of two or more diffuse regions.

Suitable materials for a fiber diffuser can include, but are not belimited to, the materials of the light guide core or light guidecladding, ground glass, silver coated glass, gold coated glass, TiO2,and other materials that will scatter and not significantly absorbed thelight wavelength of interest. One method that can be used to create auniform diffuser in a light guide, optical component, or materials is toutilize scattering centers on the order of at least 50 nanometers to 5micrometers in size. The scattering centers can have a distributionabout 200 nanometers in size.

The diverting features and focusing features suitable for focusing lightaway from the tip of the light guides herein can include, but are not tobe limited to, those having a convex surface, a gradient-index (GRIN)lens, and a mirror focus lens.

Power Sources

The power sources suitable for use herein can include various types ofpower sources including lasers and lamps. Suitable lasers can includeshort pulse lasers on the sub-millisecond timescale. In someembodiments, the power source can include lasers on the nanosecond (ns)timescale. The lasers can also include short pulse lasers on thepicosecond (ps), femtosecond (fs), and microsecond (us) timescales. Itis appreciated that there are many combinations of laser wavelengths,pulse widths and energy levels that can be employed to achieve plasma inthe balloon fluid of the catheters illustrated and/or described herein.In various embodiments, the pulse widths can include those fallingwithin a range including from at least 10 ns to 200 ns. In someembodiments, the pulse widths can include those falling within a rangeincluding from at least 20 ns to 100 ns. In other embodiments, the pulsewidths can include those falling within a range including from at least1 ns to 5000 ns.

Exemplary nanosecond lasers can include those within the UV to IRspectrum, spanning wavelengths of about 10 nanometers to 1 millimeter.In some embodiments, the power sources suitable for use in the cathetersystems herein can include those capable of producing light atwavelengths of from at least 750 nm to 2000 nm. In some embodiments, thepower sources can include those capable of producing light atwavelengths of from at least 700 nm to 3000 nm. In some embodiments, thepower sources can include those capable of producing light atwavelengths of from at least 100 nm to 10 micrometers (μm). Nanosecondlasers can include those having repetition rates of up to 200 kHz. Insome embodiments, the laser can include a Q-switchedthulium:yttrium-aluminum-garnet (Tm:YAG) laser. In some embodiments, thelaser can include a neodymium:yttrium-aluminum-garnet (Nd:YAG),holmium:yttrium-aluminum-garnet (Ho:YAG), erbium:yttrium-aluminum-garnet(Er:YAG), excimer laser, helium-neon laser, carbon dioxide laser, aswell as doped, pulsed, fiber lasers.

Pressure Waves

The catheters illustrated and/or described herein can generate pressurewaves having maximum pressures in the range of at least 1 megapascal(MPa) to 100 MPa. The maximum pressure generated by a particularcatheter will depend on the power source, the absorbing material, thebubble expansion, the propagation medium, the balloon material, distanceof measurement from plasma epicenter, and other factors. In someembodiments, the catheters illustrated and/or described herein cangenerate pressure waves having maximum pressures in the range of atleast 2 MPa to 50 MPa. In other embodiments, the catheters illustratedand/or described herein can generate pressure waves having maximumpressures in the range of at least 2 MPa to 30 MPa. In yet otherembodiments, the catheters illustrated and/or described herein cangenerate pressure waves having maximum pressures in the range of atleast 15 MPa to 25 MPa. In some embodiments, the catheters illustratedand/or described herein can generate pressure waves having peakpressures of greater than or equal to 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa,6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, 20 MPa, 21 MPa, 22 MPa, 23 MPa, 24MPa, or 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa,33 MPa, 34 MPa, 35 MPa, 36 MPa, 37 MPa, 38 MPa, 39 MPa, 40 MPa, 41 MPa,42 MPa, 43 MPa, 44 MPa, 45 MPa, 46 MPa, 47 MPa, 48 MPa, 49 MPa, or 50MPa. It is appreciated that the catheters illustrated and/or describedherein can generate pressure waves having operating pressures or maximumpressures that can fall within a range, wherein any of the forgoingnumbers can serve as the lower or upper bound of the range, providedthat the lower bound of the range is a value less than the upper boundof the range.

Therapeutic treatment can act via a fatigue mechanism or a brute forcemechanism. For a fatigue mechanism, operating pressures would be aboutat least 0.5 MPa to 2 MPa, or about 1 MPa. For a brute force mechanism,operating pressures would be about at least 20 MPa to 30 MPa, or about25 MPa. Pressures between the extreme ends of these two ranges may actupon a treatment site using a combination of a fatigue mechanism and abrute force mechanism.

The pressure waves described herein can be imparted upon the treatmentsite from a distance within a range from at least 0.1 millimeters (mm)to 25 mm extending radially from a longitudinal axis of a catheterplaced at a treatment site. In some embodiments, the pressure waves canbe imparted upon the treatment site from a distance within a range fromat least 10 mm to 20 mm extending radially from a longitudinal axis of acatheter placed at a treatment site. In other embodiments, the pressurewaves can be imparted upon the treatment site from a distance within arange from at least 1 mm to 10 mm extending radially from a longitudinalaxis of a catheter placed at a treatment site. In yet other embodiments,the pressure waves can be imparted upon the treatment site from adistance within a range from at least 1.5 mm to 4 mm extending radiallyfrom a longitudinal axis of a catheter placed at a treatment site. Insome embodiments, the pressure waves can be imparted upon the treatmentsite from a range of at least 2 MPa to 30 MPa at a distance from 0.1 mmto 10 mm. In some embodiments, the pressure waves can be imparted uponthe treatment site from a range of at least 2 MPa to 25 MPa at adistance from 0.1 mm to 10 mm. In some embodiments, the pressure wavescan be imparted upon the treatment site from a distance that can begreater than or equal to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm,0.7 mm, 0.8 mm, or 0.9 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8mm, 9 mm, or 10 mm, or can be an amount falling within a range betweenany of the foregoing.

It should be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the content and/or context clearly dictates otherwise. It shouldalso be noted that the term “or” is generally employed in its senseincluding “and/or” unless the content or context clearly dictatesotherwise.

It should also be noted that, as used in this specification and theappended claims, the phrase “configured” describes a system, apparatus,or other structure that is constructed or configured to perform aparticular task or adopt a particular configuration. The phrase“configured” can be used interchangeably with other similar phrases suchas arranged and configured, constructed and arranged, constructed,manufactured and arranged, and the like.

As used herein, the recitation of numerical ranges by endpoints shallinclude all numbers subsumed within that range, inclusive (e.g., 2 to 8includes 2, 2.1, 2.8, 5.3, 7, 8, etc.).

It is recognized that the figures shown and described are notnecessarily drawn to scale, and that they are provided for ease ofreference and understanding, and for relative positioning of thestructures.

The headings used herein are provided for consistency with suggestionsunder 37 CFR 1.77 or otherwise to provide organizational cues. Theseheadings shall not be viewed to limit or characterize the invention(s)set out in any claims that may issue from this disclosure. As anexample, a description of a technology in the “Background” is not anadmission that technology is prior art to any invention(s) in thisdisclosure. Neither is the “Summary” or “Abstract” to be considered as acharacterization of the invention(s) set forth in issued claims.

The embodiments described herein are not intended to be exhaustive or tolimit the invention to the precise forms disclosed in the followingdetailed description. Rather, the embodiments are chosen and describedso that others skilled in the art can appreciate and understand theprinciples and practices. As such, aspects have been described withreference to various specific and preferred embodiments and techniques.However, it should be understood that many variations and modificationsmay be made while remaining within the spirit and scope herein.

It is understood that although a number of different embodiments of thecatheter systems have been illustrated and described herein, one or morefeatures of any one embodiment can be combined with one or more featuresof one or more of the other embodiments, provided that such combinationsatisfies the intent of the present invention.

While a number of exemplary aspects and embodiments of the cathetersystems have been discussed above, those of skill in the art willrecognize certain modifications, permutations, additions andsub-combinations thereof. It is therefore intended that the followingappended claims and claims hereafter introduced are interpreted toinclude all such modifications, permutations, additions andsub-combinations as are within their true spirit and scope, and nolimitations are intended to the details of construction or design hereinshown.

What is claimed is:
 1. A catheter system for treating a treatment sitewithin or adjacent to a blood vessel, the catheter system comprising: apower source; a light guide that receives power from the power source,the light guide having a distal tip, the light guide emitting lightenergy in a direction away from the distal tip; and a plasma target thatis spaced apart from the distal tip of the light guide by a target gapdistance, the plasma target being configured to receive light energyfrom the light guide so that a plasma is generated at the plasma targetupon receiving the light energy from the light guide, the plasma targetbeing at least partially formed from one of tungsten, tantalum,platinum, molybdenum, niobium, and iridium.
 2. The catheter system ofclaim 1 wherein the power source is a laser and the light guide is anoptical fiber.
 3. The catheter system of claim 1 further comprising aninflatable balloon that encircles the distal tip of the light guide, theplasma target being positioned within the inflatable balloon.
 4. Thecatheter system of claim 1 wherein the target gap distance is greaterthan 1 μm.
 5. The catheter system of claim 1 wherein the target gapdistance is greater than 100 μm.
 6. The catheter system of claim 1wherein the plasma target has one of a substantially circular, square,rectangular, oval, pentagonal, hexagonal, octagonal, polygonal,trapezoidal or diamond-shaped cross-sectional configuration.
 7. Thecatheter system of claim 1 further comprising a guidewire lumen, thelight guide being coupled to the guidewire lumen.
 8. The catheter systemof claim 1 wherein the plasma target has a target face that receives thelight energy from the light guide, the target face being angled relativeto a direction the light energy is emitted to the plasma target.
 9. Thecatheter system of claim 8 wherein the target face has an angle that isgreater than zero degrees and less than 180 degrees relative to adirection the light energy is emitted to the plasma target.
 10. Thecatheter system of claim 8 wherein the plasma target has a target facethat receives the light energy from the light guide, the target facehaving an angle that is greater than approximately 45 degrees and lessthan approximately 135 degrees relative to a direction the light energyis emitted to the plasma target.
 11. The catheter system of claim 1wherein the light guide includes a distal region having a longitudinalaxis, and wherein the direction the light energy is emitted issubstantially along the longitudinal axis of the distal region.
 12. Thecatheter system of claim 1 wherein the light guide includes a distalregion having a longitudinal axis, and wherein the direction the lightenergy is emitted is angled relative to the longitudinal axis of thedistal region.
 13. The catheter system of claim 1 further comprising aplurality of plasma targets that are spaced apart from the distal tip ofthe light guide, at least one of the plurality of plasma targets beingconfigured to receive light energy from the light guide.
 14. Thecatheter system of claim 1 wherein the plasma target is furtherpartially formed from one of magnesium oxide, beryllium oxide, tungstencarbide, titanium nitride, titanium carbonitride and titanium carbide.15. The catheter system of claim 1 wherein the plasma target is furtherpartially formed from a ceramic material.
 16. The catheter system ofclaim 1 wherein the plasma target is mechanically coupled to the lightguide.
 17. The catheter system of claim 1 wherein the plasma target ismechanically uncoupled from the light guide.
 18. The catheter system ofclaim 1 further comprising a guidewire lumen, wherein the plasma targetat least partially encircles the guidewire lumen.
 19. The cathetersystem of claim 1 wherein the plasma target has a target face thatreceives light energy from the light guide, the target face includingone or more surface features.
 20. The catheter system of claim 19wherein the one or more surface features includes at least one of anindentation and a projection.
 21. The catheter system of claim 19wherein the target face includes one of a beveled edge, a conicalconfiguration, a pyramidal configuration, a dome-shaped configuration, aconcave configuration, a convex configuration, a multi-facetedconfiguration, a coiled configuration, a spring-like configuration, anda somewhat spiral configuration.
 22. The catheter system of claim 1wherein the plasma target is movable relative to the light guide. 23.The catheter system of claim 1 wherein the plasma target isspring-loaded.
 24. The catheter system of claim 1 further comprising aguidewire lumen, wherein the plasma target is coupled to the guidewirelumen.
 25. The catheter system of claim 1 further comprising a secondlight guide that receives power from the power source, the second lightguide having a second distal tip, the second light guide emitting lightenergy in a direction away from the second distal tip toward the plasmatarget, the plasma target being spaced apart from the second distal tipof the second light guide, the plasma target being configured to receivelight energy from the second light guide so that a second plasma isgenerated at the plasma target upon receiving the light energy from thesecond light guide.
 26. The catheter system of claim 1 furthercomprising a second light guide and a second plasma target, the secondlight guide receiving power from the power source, the second lightguide having a second distal tip, the second light guide emitting lightenergy in a direction away from the second distal tip toward the secondplasma target, the second plasma target being spaced apart from theplasma target and the second distal tip of the second light guide, thesecond plasma target being configured to receive light energy from thesecond light guide so that a second plasma is generated at the secondplasma target upon receiving the light energy from the second lightguide.
 27. A catheter system for treating a treatment site within oradjacent to a blood vessel, the catheter system comprising: a powersource; a light guide that receives power from the power source, thelight guide having a distal tip, the light guide emitting light energyin a direction away from the distal tip; and a plasma target that issecured to the light guide, the plasma target being at least partiallyformed from one of tungsten, tantalum, platinum, molybdenum, niobium,and iridium, the plasma target including a target face that is spacedapart from the distal tip of the light guide by a target gap distance,the target face being configured to receive light energy from the lightguide so that a plasma is generated at the target face upon receivingthe light energy from the light guide, the target face being angledrelative to a direction the light energy is emitted to the plasmatarget.
 28. The catheter system of claim 3 wherein the balloon includesa drug-eluting coating.
 29. A catheter system for treating a treatmentsite within or adjacent to a blood vessel, the catheter systemcomprising: a power source; a light guide that receives power from thepower source, the light guide having a distal tip, the light guideemitting light energy in a direction away from the distal tip; and aplasma target that is spaced apart from the distal tip of the lightguide by a target gap distance, the plasma target being configured toreceive light energy from the light guide so that a plasma is generatedat the plasma target upon receiving the light energy from the lightguide, the plasma target having a substantially circular cross-sectionalshape.
 30. The catheter system of claim 29 wherein the plasma target isat least partially formed from one of tungsten, tantalum, platinum,molybdenum, niobium, and iridium.